The fraction \(\lambda _{0}\)  of black holes from the zero-spin formation channel is constrained to be less than \(0.32\)  at the \(99\%\)  credible level, and is consistent with \(\lambda _{0}=0\) .
Therefore, these GW observations suggest that at least some 1G+1G  binary black holes have spinning components, consistent with [1]}, and not all 1G  black holes have extremely low (\(< 0.01\) ) spins as would be expected if all progenitor stars had efficient angular momentum transfer [2]}.
We find that \(90\%\)  of 1G+1G  primary black holes have a spin magnitude less than \(0.57\) .
